1. Field of the Invention
The present invention relates to improved flight information displays. In particular, the present invention relates to improved flight information computation and displays which show the maneuver space for a target aircraft and its conflict regions with other aircraft.
2. Description of the Prior Art
FIG. 1A (Prior Art) shows a typical cockpit display of flight information (CDTI), which provides each pilot with a map view of the location of his or her own aircraft (the “ownship”) and the locations of other nearby aircraft (“traffic”). A map view is simply the typical “bird's-eye” view that one would get by looking down on a scene from above. In FIG. 1A, alphanumeric data tags provide flight designator, airspeed, the first two digits of heading, and flight level (the first three digits of altitude) for all traffic. The display also includes a compass rose, heading information, waypoints, and ancillary flight parameters. In actual CDTIs, colored symbols are typically shown against a black background.
Research has shown that it can be extremely difficult to maneuver aircraft through a crowded airspace with a CDTI, or any other map view display (see, for example, Knecht & Hancock, “Separation maintenance in high-stress free flight using a time-to-contact base cockpit display of traffic information,” Proceedings of the 4th Annual Meeting of the Human Factors and Ergonomics Society, 16–20, 1999; and Smith, “Shared Decision Making in the National Airspace System,” Final Report, FAA Grant 93-G-048, 1998).
The primary difficulties appear to be that people are relatively ineffective at (a) predicting impending loss of separation between icons moving on flat screen displays and (b) calculating maneuver solutions to guarantee sufficient separation. Of the two problems, (b) appears the worse (Knecht & Hancock).
FIG. 1B (Prior Art) shows the display screen of the Federal Aviation Administration's Display System Replacement (DSR). The DSR is used by Air Traffic Control (ATC) on the ground. The DSR receives composite radar and other data on the locations of aircraft and displays them in a manner similar to that used by the CDTI of FIG. 1.
FIG. 2 (Prior Art) shows the shape of the FAA required “protected zone” for aircraft in the en-route flight environment. A protected zone is a cylindrical buffer region of airspace surrounding each aircraft which by law should not be entered by another aircraft. In the en-route flight environment, the radius of this zone is normally 5 nautical miles (nm), while the half height is normally either 1000 or 2000 feet, depending on altitude.
A technology called the conflict probe exists in the prior art. An example of this technology is described in Neidringhaus et al., “Automated En Route Air Traffic Control (AERA) algorithmic specifications: Vol. 3. Flight plan conflict probe,” Report No. DOT/FAA/ES-83/6. Briefly, conflict probe technology is a software algorithm which takes current x, y, z positions of aircraft in the area, together with their velocities and flight plans, and “looks ahead in time” to predict their positions in space approximately 8 to 20 minutes into the future. This algorithm allows potential conflicts between aircraft to be identified far enough in advance to allow tactical avoidance maneuvers to be selected and comfortably executed.
The DSR of FIG. 1B (Prior Art), together with the protected zone of FIG. 2 and the conflict probe algorithm for predicting minimum separation between aircraft, constitute tools and concepts currently used by air traffic controllers to keep track of aircraft and maintain safe separation.
This prior art has two major limitations. First, current visual traffic information displays are, virtually without exception, map-based. Maps present one view only, and consequently are a poor method of displaying the trajectory information necessary to identify three dimensional traffic conflicts. Map displays are two-dimensional, and are therefore incapable of presenting more than a partial set of conflict-resolution solutions.
The second major limitation in the prior art is more subtle. While it seems obvious to use three-dimensional coordinates in displays, these three dimensions are not the most effective or intuitive way for pilots and air traffic controllers to note conflicts and select maneuvers. Other multidimensional representations that are more directly related to achievable maneuvers are needed.
Two needs remain in the art for improved flight information displays. First, commercial and general aviation pilots need a display which clearly and rapidly shows the entire set of maneuvers they can safely make to avoid obstacles such as traffic, weather, terrain, and special-use airspace, while still adhering to letters of agreement (LOAs) between sectors regarding how traffic will flow. Second, air traffic controllers need a similar display to augment the DSR; one which shows the maneuvers they can safely issue to a aircraft to negotiate obstacles and maintain LOAs.